Cranial Nerves (VII-XII) Flashcards
Functions of Facial Nerve
Motor SVE - muscles of face (facial
expression) and scalp, stapedius muscle, posterior belly of digastric, stylohyoid muscles
Sensory SVA - taste from anterior 2/3 of tongue from floor of mouth and palate
Sensory GSA - sensation from a small region near the external auditory meatus
Parasympathetic GVE - secretomotor to submandibular and sublingual glands, lacrimal glands and glands of nose and
palate
Carries brachial motor fibers for facial expression
Main Trunk
In facial nerve, Carries fibers for PSY (tearing and salivation), taste, and GSA
Nervus Intermedius
3 nuclei of facial nerve
- Main Motor Nucleus
- Parasympathetic Nuclei
● Superior salivatory nucleus
● Lacrimal nucleus - Sensory Nucleus
● Nucleus tractus solitarius
● Trigeminal nucleus
Facial nucleus
Lies deep in the reticular formation of the
lower part of the pons
Part of the nucleus supplies muscles of the
upper part of the face receives fibers from
both cerebral hemispheres
Main Motor Nucleus
Motor cortex supplying lower part of face
contralateral side of motor
cortex
Motor cortex supplying upper part of face
both sides of motor cortex
facial nuclei that Lie posterolateral to the main motor nucleus
parasympathetic nuclei
Parasympathetic nucleus of facial nerve that receives afferent fibers from thalamus through descending autonomic pathways
Superior Salivatory Nucleus
PSY facial nuclei that Receives afferent fibers from hypothalamus
for emotional responses and from sensory
nuclei of trigeminal nerve for reflex
lacrimation due to irritation
Lacrimal Nucleus
has Afferent fibers: geniculate ganglion of CN VII
Efferent fibers cross midline and ascend to VPM of opposite thalamus
Nucleus of Tractus Solitarius
Upper part (rostral) of nucleus of tractus solitarius
sensory nuclei
● formed of Central processes of unipolar cells of
geniculat ganglion
● Also contain efferent preganglionic PSY
fibers from parasympathetic nuclei
Sensory Root (nervus intermedius)
lies in the genu and
contains primary sensory neurons for taste in anterior ⅔ of tongue, GSA for a region
near external auditory meatus
Geniculate ganglion
Main portion of facial nerve exits the skull through
stylomastoid foramen
facial nerve Pass through the parotid gland and divides
to 5 major brachial motor branches that control facial expression
○ Temporal
○ Zygomatic
○ Buccal
○ Mandibular
○ Cervical
○ Other smaller motor branches
innervate the stapedius, occipitalis,
posterior belly of digastric, and
stylohyoid muscles
Dampen movements of middle ear
ossiclesproviding feedback
modulation of acoustic signal
intensity
stapedius
tensor tympani innervated by
trigeminal
carried by greater
petrosal nerve (takes off the main trunk of CN VII) to reach sphenopalatine
(pterygopalatine) ganglion where
postganglionic PSY project to lacrimal
glands and nasal mucosa
Preganglionic PSY fibers from Superior
Salivatory Nucleus
leaves CN VII just before
the stylomastoid foramen and travels back
upward to traverse the middle ear cavity
before exiting the skull at the petrotympanic
fissure, just medial to the TMJ.
Chorda tympani
Chorda tympani carry
SVA taste for anterior
⅔ of tongue
taste from
posterior ⅓ tongue and
pharynx
CN IX and X
Chorda tympani Synapse with rostral
nucleus
solitarius (gustatory nucleus)
Ascending projections of chorda tympani travel via
____ to VPM then
to cortical gustatory area
central tegmental tract
inferior margin of the
postcentral gyrus adjacent to tongue
somatosensory area and extends
into the fronto-parietal operculum
and insula
BA 43
submandibular and sublingual glands,
nasal, and palatine glands
Superior salivatory nucleus
UMN LESION VS LMN LESION
UMN lesion - contralateral side EXCEPT FOREHEAD
LMN lesion - affects whole face
2 components and function of vestibulocochlear nerve (CN VIII)
Vestibular: SSA
- from utricle and
saccule and semicircular
canals - position and
movement of head
Cochlear: SSA
- organ of Corti -
hearing
respo for head position and head movement
● Utricle and saccule - head position
● Semicircular canals - head movement
Vestibular Nucler Complex
● 4 Nuclei
- Beneath floor of 4th ventricle
- Lateral vestibular nucleus
- Superior vestibular nucleus
- Medial vestibular nucleus
- Inferior vestibular nucleus
The nerve fibers of the vestibular nerve are the central
processes of nerve cells located in the
ganglion, situated in internal acoustic meatus
The vestibular nuclei receive afferent fibers from
the utricle and saccule and the semicircular canals
through the vestibular nerve and fibers from the cerebellum
through
inferior cerebellar peduncle
Efferent fibers from the nuclei pass to the cerebellum through the
inferior cerebellar peduncle.
The cochlear nerve conducts nerve impulses concerned
with sound from the
organ of corti in the cohclea
The
fibers of the cochlear nerve are the central processes of
nerve cells located in the
spiral ganglion of cochlea
On entering the pons, the nerve fibers of cochlear nerve
divide, with two branches entering the
posterior and anterior cochlear nucleus, respectively
Send axons that run medially through pons
to end in
trapezoid body and the
olivary nucleus
cochlear nuclei ascend through post parts of of pons and midbrain as
lateral lemniscus
As these cochlear fibers ascend, some
of them relay in small groups of nerve cells, collectively
known as the
nucleus of the lateral lemniscus
he primary auditory cortex (areas 41 and 42) includes
what gyrus
gyrus of Heschl on the upper surface of the superior
temporal gyrus
gyrus of Heschl in what cortex
primary auditory cortex
The recognition and interpretation
of sounds, on the basis of past experience, take place in
the
secondary auditory area
components and functions of glossopharyngeal nerve (CN IX)
● SVE- stylopharyngeus muscle- swallowing
● GVE- secretomotor PSY to parotid gland
● SVA- taste from posterior ⅓ of tongue and
pharynx
● GVA- carotid sinus (baroreceptor) and
carotid body (chemoreceptor)
● GSA- general sensation to middle ear, region near external auditory meatus, pharynx, and posterior ⅓ of tongue
Parasympathetic nucleus of CN IX
inferior salivary nucleus
component, muscle, and nucleus responsible of elevating the pharynx when talking or
swallowing and contributes to gag
reflex
SVE - brachial motor portion
stylopharyngeus
nucleus ambiguus
PSY vagal leave via _____ and
then joins the lesser petrosal nerve
to synapse in the optic ganglion to
the parotid gland
tympanic nerve
three nucleus of glossophargyngeal nerve
(1) the
main motor nucleus,
(2) the parasympathetic nucleus - inferior salivatory nucleus
(3) the sensory nucleus - nucleus solitarius
GVA and SVA in CN IX
inferior (petrosal)
glossopharyngeal ganglion
GSA in IX
to inferior and superior (jugular)
glossopharyngeal ganglion
main motor nucleus of CN IX Lies deep in reticular formation of medulla
and is formed by
sup end of nucleus ambiguus
supplies stylopharyngeus muscle
main motor nucleus
reflex involving the
glossopharyngeal and vagus nerves helps
assist regulation of blood pressure
carotid sinus reflex
